Money taken off my cashapp I didn’t want

Hey! So for some reason I keep getting this notification on cashapp from Apple saying “not enough cash to take $7.68” and I’m always like that’s fine because I don’t know why they’re trying to take money from my cashapp I don’t pay for anything, and then somebody sent me $20, and you guys took $16.46 and I think there was a mistake and would really like that money back